Projectile



J. R. JAssE PROJECTILE Dec' 30 2 SHEETS-SHEET 2 Filed Feb. 13, 1950tangential acceleration, the longitudinal acceleration followed bydeceleration, and the centrifugal force, to drive the hollow charge inthe opposite direction to the body I, since for each ball-bearing, andfor example for the front ballbearing, by the action of the violentlongitudinal acceleration which occurs as soon as the shot is fired, theballs I4 are heavily pressed against the rear bearing surface I5,thereby making it impossible for any sliding of said balls to occurrelatively to said bearing surface. The balls then effect a rollingmovement on said bearing surface I5, and rotate, on the one hand aboutthemselves about a diameter at right angles to the axis X-X, and on theother hand about said axis. This latter rotation gradually produces onthe balls a considerable centrifugal force which presses them heavilyagainst the outer race I9 and prevents any sliding of said ballsrelatively to said race. The balls then effect a further rollingmovement which results in said Iballs rotating about the axis X-,X andabout their diameter Which is inclined at 45 to said axis X-X. Owing tothis rotation of the balls about said diameter, the balls acquire, attheir point of contact with the front bearing surface I'I and with theinner race I8, a speed with respect to said surface which is in theopposite direction to their speed with respect to the rear surface I5and the outer surface I9. The sliding friction between the balls and thesurface I8 and, later (at the instant of the deceleration), the frontbearing surface I1, tends to eliminate this relative speed between theballs I4 and said bearing surfaces I1 and I8 and consequently to drivethe hollow charge in the opposite direction to the body I.

It is therefore possible, by suitably choosing the diameter of the ballsI4 and 20, to arrange for this tendency of the hollow charge to rotatein the opposite direction to the body I to compensate almost exactly thetendency to direct rotation due to the friction of the ball-bearing andthat of the abutment pivot (I0, I I).

By way of example, for a hollow charge weighing about 1.5 kg. and for aprojectile of a calibre of about 120 mm., the speed of gyration of whichis about 400 revolutions per second, the desired result, i. e. apractically complete immobilization of the hollow charge, is obtained byusing a balldiameter of about 10 mm.

As hereinbefore stated, the gyration of the body I may be obtained:either by firing said body in a ried gun, the body I being in this caseprovided with a usual riling band and it being possible for the rearcompartment to contain another explosive, incendiary, smoke-producing,or like charge, or merely a self-propulsive charge with or Withoutgyratory action, or guiding devices, or the like; or by using theejection through suitably inclined nozzles of pressure gases produced bythe combustion of a charge of powder contained in the rear compartment,said charge automatically producing Iboth the propulsion and thegyration.

This latter solution is the one which has been illustrated and whichwill now be described.

It should first be noted that, owing to the fact that the stabilizationof the projectile is obtained by means of the rotation of only a portionof the projectile, and that hollow charge projectiles have their centreof gravity located very much to the rear, it is necessary to impart tothe projectile a speed of gyration two to three times greater than inthe usual projectiles.

The rear compartment of the projectile therefore contains theself-propulsion and self-gyration charge. This charge is formed by anumber of concentric coaxial cylindrical cakes of powder 24, 25, 26, Z'I(Figs. 1 to 3) The peripheral cylinder 24 is directly housed in the bodyI of the projectile, between a front shoulder 28 of said body and a rearnozzle-supporting member 29 screwed at 30 in the tapped rear end of saidbody. Said cylinder 24 of powder is slit at 3I (Fig. 2) along its entirelength, so as to enable it to follow exactly the deformations of saidbody for the reasons which will be analysed hereinafter and also inorder to facilitate its insertion.

Preferably, between the cake 24 and the body l is interposed a coat 32of a varnish, for example a thermoplastic resin, which adheres perfectlyboth to the metal and the powder, while allowing for small deformationswhich are different for the metal and for the powder.

As regards the other cakes 25, 26, 2, which are coaxial with the axisX-X, they are mounted in the projectile so as to ybe free from therotation of body I, since they are held between: on the one hand astar-shaped front grating 33, for example with three arms, provided withprojections 34 between which said cakes are engaged; and on the otherhand a rear grating comprising radial bars 35 provided on their frontface with projections 36 for separating the cakes.

The front grating 33 is adapted to bear, by means of a ball 31, againstthe bottom of a cup 38 provided in the rear wall of the web 2 of thebody I. Said cup is surrounded by a cylindrical baffle 38a which issupported by the grating and is stuffed with grease.

As regards the rear grating 35 it is supported, by means of a ball 39housed in a cavity iii provided at the centre of said grating, by anintermediate element 4I which in turn bears against an adjusting screw42 screwed in a tapped hole 43 provided at the centre of the rear member29 that supports the ejection nozzles for the propulsion gases producedby the combustion ci the cakes of powder 24 to 2l. A cylindrical baffle43a which is carried by the member 29 and is lled with grease surroundsthe cavity 5%.

As regards the cakes 25 and 26, on their mu.-

tually facing surfaces, small portions of said surfaces adjacent to thepoints of contact with the corresponding projections 35 of the bars 35are covered with an insulating material i4 (Fig. 3) which may be of thesame nature as that of the aforesaid varnish 32 and which preventsignition. so that the cakes burn in the manner shown by the dotted linesin Fig. 3.

The propulsion and the gyration are effected by means of a series ofperipheral nozzles 45 which are merely tted into holes provided with ashoulderd in the member 25; said nozzles are held in position merely bythe thrust exerted on them, from the front' towards the rear, by theaforesaid gases. The longitudinal axes Y-Y of said nozzles 45 areinclined with respect to the plane of Fig. l in such a-manner that thegases which issue from the nozzles cause the body I to rotate about itslongitudinal axis X-X. The inclination may for example be between l5 and20 for a distance between the axes Y-Sf and X-X 0f about 35 mm. for aprojectile of a calibre of mm.

There is furthermore provided an additional axial nozzle 4l which isnormally closed by a disc 4B, for example of copper or aluminium, whichis intended to blow out if, for any reason. and in particular in theevent of the temperature of the block of powder` at the instant when themounting the exception .of the outer cake '24,1the ,cakes 25,

'shot-isred exceeding forexample 25 C., the pressure lof the gasesYinside the compartment 4 exceeds a given Ymaximum value thatcorrespends tothe pressure for which the strength of the body has beencalculated (for example -web .2, the electric .conductors `for firing,not

shown, .being `located for .example between ltwo Vof the cakes of powderand leading out at the rear 4through one of the nozzles.

The projectile V:operates as follows:

-Villien the shot is fired, which .is effected by the primer pt thecharge 2l) is ignitedby thc pellet 61| It should be noted that, owingrto the pivotal 10i .all the .powder .in the body I, with 26 :2l .onlyparticipate slightly .in .the erraten' movement, so 4that these cakesare to a great extent `shieltlergl from the centrifugal and tanecntalaceleratons.

During the combustion of Athe powder, the balls 3l and M39 that formpivots are protected from the flames Vby -means of grease-that fill-sthe battles iliandll.

It should .be noted, on the other hand, that the cake '24, owl-fig tothe fact that it only :burns with its .inner surface 5d, protects the'body i from a rise of temperature and vmoreover facilitates .thelighting of the powder by preventing a .powder surface to be lightedbeing placed opposite .the cold .wall of the metal body.

The .gases produced by the combustion of the powder are .ejected throughthe nozzles `l and simultaneously .effect .the propulsion -cf ltheprojectile .and .the .gyratien of the body 'l about the axis ,X--Xwithout .the gyration .of the hollow charge for .the reasonshereinbefore explained.

lf., at any instant, the .pressure in thecompartinjuring the ringattendants) and the central j nozzle AT1 adds its propulsive `action tothat of the peripheral nozzles 55. This la rrangement enables thehighest emciency ci the :iet device and therefore L11-n range to beobtained for the -mos. u al amera-ture conditions, for example 28 no"above that temperature, through the op g of the central nozzle, theinternal pressure falls below the optimum value.

Owing to the .Very .high .speed of gyration required Afor a hollowcharge projectile, 'hereinbe-fore explained. this vhigh speed produces aconsiderable centrifugal force. This centrifugal force increasesthroughout the duration of the oombulstion .of the charge of powder (i.e. l to Z tenths .of .a second) and as the projectile mov-es along itstrajectory. Said centrifugal force `acts on the body l as a radialpressure p1.

Consequently, if it is desired, in order to obtain the vhighestspeci-fic efficiency of the jet, to subject the metal `throughout theentire duration of the 4com'bustion to a Vstress approaching its elasticlimit, it is necessary to arrange for the total-pressure P (Fig. l), dueto thecombined action ofthe aforesaid pressure p1 and the pressure 1132due to the gases exerted in the com-partment 4,'to be lkept constant;for this purpose the pressure p2 must vary in 'the opposite direction tothe pressure p1.

This result can be obtained for example: either by the combined use of ahighly exothermic powder and nozzles capable of undergoing a rapid andcontrolled erosion bythe action of the gases; thus, it is possible touse balistite as the powder and make the nozzles of a low-carbon steel,for exampleabout '1 per cent, or, as known, by suitably-choosing theshape of 'the cakes of powder, so as 'to provide a combustion surfacesuch that it -decreases as a function .of the time.

lFig. -4 shows, in order to give a more Vdefinite idea, the variationsof p1 (curve A), of p2 (curve B') and of Papi-+132 -(curve C) as afunction of `the time t or, what uamounts `to the same thing, theI'positions of the projectile along .its 'trajectory. The absc'issa .t1correspond to the Yend of the combustion of the ypropulsive charge.

Figs. 5 and 6 show modications in the manner of constructing the nozzles5I, which are directly formed "in the .member fixed to the end of thebody I.

In the example of Fig. 5, said member 52 is merely adapted to bear bymeans of a shoulder `53 against the inner face of an inwardly projectingange 54 provided lat the rear end of the body l, whereas in the exampleof Fig. 6, `the member 55 is screwed at 56, as in the example of Fig. 1,in the tapped end of the body l.

Naturally, the invention is in no way'restricted to the embodimentsillustrated and described, which have only been chosen by way ofexample.

The non-rotary hollow charge is only taken lby way of example of anembodiment and may be replaced by any other device that has to beshielded from .the action of the centrifugal force, such as arself-guiding device, lifting surfaces, .or the like.

Optionally, the casing .5 .of the hollow charge could be provided withprojections which would make it possible, by .ring the projectile from ariifled tube, to impart .to Vsaid .charge an .initial rotation .in theopposite .direction to that of the body I so that, when the impactoccurs, the rotation of the hollow charge is substantially eliminated bythe frictional forces which tend to rotate it in the direction Yof saidbody l.

Of course, :the cakes of powder could be fixed inside the jet device andAnot freely mounted as shown- Having described my invention what 1 claimas new and desire to secure by .Letters Patentis:

.1- Il. al 'gyroollca'lly stabilized projectile, .an outer body .oflrevolution about .a longitudinal axis, .said body :being provided withat least one cavity which is roper! at the :front of said body and witha transverse partition which terminates said cavity at the rear thereof,a hollow charge housed in said cavity and formed by a hollow container.of generally oi-conical shape coaxial to .said'bod-y, by asubstantially conical wall housed said container lin such a mann-er thatits apex is turned towards the rear of said container in which it formsa front chamber and a rea-r chamber with a concave front face, and by.an Aexplosive charge located in said rear chamber,

pivoting means coaxial to said axis and interposed between saidcontainer and said transverse partition, a first ball bearing mountedbetween the lateral wall of said cavity and said container in the regionof its largest cross-section, and a second ball bearing between saidwall and said container near said pivoting means,

2. A gyroscopically stabilized self-propelled projectile comprising incombination: an outer body which is a body of revolution about alongitudinal axis and which is provided with a front cavity and a rearcavity separated by a transverse partition, an explosive charge ofpowder which is placed in said front cavity, a transverse support xed tosaid body in the rear end of Said rear cavity, a set of nozzles carriedby said support and through which said rear cavity opens into theatmosphere, a charge of self-propulsion powder housed in said rearcavity for producing propulsion gases which are ejected through saidnozzles, at least one portion of said charge being mounted freely insaid rear cavity about said longitudinal axis and being free from therotation of said body, a front grating with radial bars which isarranged parallel to said transverse partition and against which saidfreely mounted portion of the propulsion charge is adapted to bear fromthe rear towards the front, a front pivot between said transversepartition and said front grating, a rear grating with radial barsagainst which the rear end of said freely mounted portion of theself-propulsion charge is adapted to bear from the front towards therear, and a central pivot device interposed between said rear gratingand said nozzle support.

3. Projectile according to claim 2, wherein said central pivot devicefor pivoting the rear grating on the nozzle support comprises a ballengaged in a central cavity of said grating, a screw screwed in an axialcentral hole of said support and an intermediate element between saidball and screw, whereby an axial adjustment of the rotary portion ofsaid self-propulsion charge can be effected.

4. Projectile according to claim 2, wherein baies filled with grease arearranged respectively about said front pivot and said rear pivot devicefor the respective pivoting of the front and rear gratings in order toprotect said front pivot and said pivot device from the action of thecombustion gases of said self-propulsion charge.

5. Projectile according to claim 2, wherein means are provided forrendering the strain on said body, due to the centrifugal force and thepressure of the propulsion gases inside said body, substantiallyconstant throughout the entire duration of combustion of saidself-propulsion charge.

6. Projectile according to claim 5, wherein said means comprise thecombination of a highly exothermic powder that forms saidself-propulsion charge, with nozzles which are made of a materialcapable of undergoing corrosion by the action of the propulsion gases.

7. Projectile according to claim 2, wherein said self-propulsion chargeis formed by balistite which is a highly exothermic powder, and saidnozzles are made of steel capable of corrosion that contains about 1 ofcarbon, whereby, owing to the heat of the propulsion gases, the nozzlescorrode and produce a drop in the pressure exerted by said gases on thewall of said body, which is substantially the reverse of the variation 8of the action of the centrifugal force on said body, in such a mannerthat said body is subjected to a substantially constant strain by thecombined action of said centrifugal force and said pressure due to saidgases.

8. Projectile according to claim 2, further comprising, for attenuatingthe variations of eciency due to the temperature, a central nozzlelocated axially in said support, a disc placed in said support behindsaid central nozzle for normally closing same, said disc being adaptedto be driven out automatically if the pressure in said body exceeds apredetermined value, and behind said disc a grating for retaining sameand preventing it being converted into a projectile.

9. A gyroscopically stabilized self-propelled projectile comprising incombination: an outer body which is a body of revolution about alongitudinal axis and which is provided with a front cavity and a rearcavity separated by a transverse partition, a hollow charge housed insaid front cavity and formed by a hollow container of generallybi-conical shape coaxial to said body, by a substantially conical wallhoused in said container in such a manner that its apex is turnedtowards the rear of said container in which it forms a front chamber anda rear chamber with a concave front face and by an explosive chargeplaced in said rear chamber, pivot means coaxial to said axis andinterposed between said container and said transverse partition, a firstball bearing mounted between the lateral wall of said front cavity andsaid container in the region of its largest cross-section, and a secondball bearing between said wall and said container near the pivot means,a transverse support xed to said body in the rear end of said rearcavity, a set of nozzles carried by said support and through which saidrear cavity opens into the atmosphere, a charge of self-propulsionpowder housed in said rear cavity for producing propulsion gases whichare ejected through said nozzles, at least one portion of said chargebeing mounted freely in said rear cavity about said longitudinal axisand being free of the rotation of said body, a front grating with radialbars which is arranged parallel to said transverse partition and againstwhich said freely mounted portion of the propulsion charge is adapted tobear from the rear towards the front, a front pivot between saidtransverse partition and said front grating, a rear grating with radialbars against which the rear end of said loosely mounted portion of theself-propulsion charge is adapted to bear from the front towards therear, and a central pivot device interposed between said rear gratingand said nozzle support.

10. In a gyroscopically stabilized projectile, an outer body ofrevolution about a longitudinal axis, said body being provided with afrontcavity, a hollow charge mounted in said cavity to be free of therotation of said body, said hollow charge being formed by a hollowcontainer of generally bi-com'cal shape coaxial to said body, by asubstantially conical Wall housed in said container in such a mannerthat its apex is turned towards the rear of said container in which itforms a front chamber and a rear chamber with a concave front face andby an explosive charge located in said rear chamber, a thrust andcentering device of very small diameter carried by the rear of saidcontainer and adapted to bear against the rear bottom of said cavity,and guiding means interposed between the lateral wall of said cavity andsaid container to center the latter. r

11. In a gyroscopically stabilized self-propelled projectile, an outerbody of revolution about a longitudinal axis, a self-propulsion chargein said body, said self-propulsion charge comprising a peripheralcylindrical cake of powder which is on the one hand externally coatedwith an inhibiting substance and on the other hand slit longitudinallyso as to be pressed resiliently against the inner face of said body.

JOSEPH RAYMOND JASSE.

REFERENCES CITED The following references are of record in the le ofthis patent:

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